This invention relates to an air suspension system and particularly to a suspension system incorporating a spring steel step spring that is connected to a hanger by a universal pivoted hanger bearing assembly. The step spring also acts as a beam having a trailing end supporting an end of a transverse bolster beam. The bolster beam provides a lower seat for the air spring. The axle is connected to an intermediate point on the step spring. Preferably the connection distributes the load such that the air spring carries two-thirds of the axle load.
This inventor is also the inventor of U.S. Pat. Nos. 3,434,707, 4,309,045, 4,465,298, and 4,541,653. The subject matter of those patents, except for that incorporated by reference in such patents, is incorporated herein by reference.
Various suspension systems have been designed and developed incorporating an air spring. Some of these air spring syspension systems have been particularly intended for conversion of existing installations. Typically these conversions involve the replacement of an existing leaf spring assembly by an air ride suspension assembly. The disadvantages of the prior art conversion suspension systems have included the fact that they are cumbersome, heavy, expensive and the conversion is difficult. Also, the prior art conversion suspensions typically do not result in a good ride because of restrictions imposed by the fact that they are conversions and not OEM systems. The suspension system of the present invention provides an excellent ride while affording easy installation.
The present suspension system is easily installed as a replacement for an existing suspension system. All of the connections are by bolts rather than by welding. Also, the entire suspension system is light weight, and yet it incorporates characteristics of a leaf spring combined with an air spring, both cooperating to produce a better ride. The suspension system can be installed on a single axle or tandem axle vehicle. In fact, there is no limit to the number of axles that the suspension system can accommodate, because each suspension system is selfcontained and not dependent upon the next one. Therefore, this suspension system is highly versatile as a conversion system. Even though all components of the suspension system are steel, the total weight is less than 500 pounds per axle.